Formation pressure measurement with remote sensors in cased boreholes

Abstract

The present invention relates to a method and apparatus for establishing communication in a cased wellbore with a data sensor that has been remotely deployed, prior to the installation of casing in the wellbore, into a subsurface formation penetrated by the wellbore. Communication is established by installing an antenna in an opening in the casing wall. The present invention further relates to a method and apparatus for creating the casing wall opening, and then inserting the antenna in the opening in sealed relation with the casing wall. A data receiver is inserted into the cased wellbore for communicating with the data sensor via the antenna to receive formation data signals sensed and transmitted by the data sensor. Preferably, the location of the data sensor in the subsurface formation is identified prior to the installation of the antenna, so that the opening in the casing can be created proximate the data sensor. The antenna can then be installed in the casing wall opening for optimum communication with the data sensor. It is also preferred that the data sensor be equipped with means for transmitting a signature signal, permitting the location of the data sensor to be identified by sensing the signature signal. The location of the data sensor is identified by first determining the depth of the data sensor, and then determining the azimuth of the data sensor relative to the wellbore.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThis invention relates generally to the determination of various parameters in a subsurface formation penetrated by a wellbore, and, more particularly, to such determination after casing has been installed in the wellbore by way of communication across the wall of the casing with remote sensors deployed into the formation prior to the installation of the casing.2. Description of the Related ArtPresent day oil well operation and production involves continuous monitoring of various well parameters. One of the most critical parameters required to ensure steady production is reservoir pressure, also know as formation pressure. Continuous monitoring of parameters such as reservoir pressure indicate the formation pressure change over a period of time, and is necessary to predict the production capacity and lifetime of a subsurface formation. Typically, formation parameters, including pressure, are monitored with wireline formation testin...

AI Technical Summary

Problems solved by technology

Each of the aforementioned patents is limited in that the formation testing tools described therein are only capable of acquiring formation data as long as the tools are disposed in the wellbore and in physical contact with the formation zone of interest.

After the wellbore has been lined with casing and the casing has been cemented, if necessary, standard electromagnetic communication from inside the wellbore with the individual remote sensors outside the casing is no longer possible.

If there is no effective means of com

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